A conventional audio emitting tread mat is shown in FIG. 7 and comprises a tread mat 1, two sheets of insulating papers 2 having conductive printing carbon powder 21 adhered to its top and bottom surfaces. A foam rubber sheet 3 having a predetermined thickness includes a plurality of holes 31 and a sound device 4 which are combined into the structure. The foam rubber sheet 3 is sandwiched between the two sheets of the insulating papers 2 and two lead wires 211, 211' are respectively connected between the top and the bottom layer of the carbon powder 21 and the input of the sound device 4.
When the tread mat 1 is stepped on by a person, the foam rubber sheet 3 is compressed, forcing the top layer and the bottom layer of carbon powder 21 to contact each other so that the sound device 4 is powered to emit sounds announcing that a visitor has arrived.
The conventional audio emitting tread mat described above is considered to have the following disadvantages:
1. The total amount of components are large in number which increases assembling work and costs; PA1 2. The lead wires cannot be connected with the layers of carbon powder by means of simple welding, but must be secured by gum tape which is easily releasable; and, PA1 3. The insertion of insulating paper in the tread mat is difficult since it folds. PA1 1. One or more air actuated transducers are first adhered on an inner surface of the bottom layer of the tread mat and then a foam rubber sheet is interposed in the tread mat to minimize assembly work and time; PA1 2. Carbon powder used in conventional audio emitting tread mats is not used to allow secured electrical coupling; PA1 3. Insulating paper used in conventional audio emitting tread mats is not used to provide a system independent of folding criteria; PA1 4. The sound device can be located in a displaced manner from the tread mat inside a house; and, PA1 5. A small insulating member is provided to be inserted in the sound device to temporarily disable the sound device during the evening.